Microcrystalline Cellulose as Graphite Exfoliation Agent and its Effect on Electrical Conductivity

• Published in: Solid state phenomena Vol. 317; pp. 144 - 151
• Main Authors: Abd Rahman, Shaharin Fadzli, Azmi, Amirul Hadi, Zainal Abidin, Mastura Shafinaz
• Format: Journal Article
• Language: English
• Published: Zurich Trans Tech Publications Ltd 10.05.2021
• Subjects: Aqueous solutions; Casting defects; Cellulose; Crystalline cellulose; Effectiveness; Electrical resistivity; Exfoliation; Graphene; Graphite; Microcrystals; Raman spectra; Raman spectroscopy; Sodium hydroxide; Solvents; Spectrum analysis; Thin films; Graphene; Ultrasonic Exfoliation; Microcrystalline Cellulose
• ISSN: 1012-0394; 1662-9779; 1662-9779
• DOI: 10.4028/www.scientific.net/SSP.317.144

Graphene has drawn a lot of attention as a promising material for a conductive ink due to its high electrical conductivity and abundant source. Selection of solvent for ink formulation is crucial to obtain the desired result. In this work, microcrystal cellulose solution is investigated as alternative solvent for conductive ink formulation. Although the viability of the microcrystal cellulose solution was already presented in other works, further thorough and systematic study is highly required. Cellulose solution was prepared using microcrystalline cellulose and sodium hydroxide aqueous solution. Dispersions with different graphite-to-cellulose ratio were prepared. The exfoliation process was for sonication times of 8, 16, 24 and 32 hours. For Raman spectroscopy and 4-point probe measurement, graphene thin film was formed by drop-casting 20μl dispersion on glossy paper. Sample with low graphite-to-cellulose ratio exhibited more significant reduction in unexfoliated graphite content over the sonication time. The sufficient amount of cellulose in the dispersion leads to more effective exfoliation process. According to analysis on the Raman spectra, the exfoliated graphite could be classified as few-layer graphene with low defect content. The drop-casted thin film from dispersion with ratio of 20:1 showed sheet resistance lesser than 100 Ω/sq. The obtained results confirmed the effectiveness of microcrystal cellulose as the agent for exfoliation process.